A centrifugal separator with radial openings is known from EP 0 804 291 B1 corresponding to DE 696 09 594 T2. The rotor of the centrifugal separator is in this case constructed with apertures in the form of radial openings in such a way that the danger of clogging or wear is reduced in the radial apertures and that, owing to a special configuration of the cross-section of the apertures, a reduction in the noise level produced and an influencing of the frequencies of the noise produced in the apertures occurs. So that this is the case, the aperture is configured in such a way that its radially inner cross-section is first of all outwardly continuous or slowly increases and then discontinuously jumps outwardly in the centre of the aperture. For this purpose, either a shape, which is first of all approximately continuous and then widens in a funnel shape, or else a transition from a continuous shape to a spherical cap or similar shape is provided. This concept may be sensible for certain applications, but has not proven to be useful to date, for example in the sugar industry.
Discontinuous centrifuges are also used, in particular, for the separation of sugar crystals from sugar crystal suspensions.
A starting material, for example a magma with an enriched crystal suspension, is fed from above, and then treated in the centrifuge drum in such a way that a product, for example a crystallisate here, is deposited on the inner surface of a casing of the centrifuge drum. The liquor, in this case, discharges through a working screen, which is located on the casing.
This crystallisate or these crystal layers then have to be cleared from the centrifuge drum so that it is ready for the next use or the next batch.
A concept of this type also to be called a periodically working centrifuge for centrifuging filling materials is already known from DE 1 916 280 B. There are provided in the centrifuge casing holes, through which the liquid separated during centrifugation from the sugar crystals is discharged to the outside and leaves the centrifuge drum.
For the cross-sectional shape of these holes, DE 1 916 280 B proposes an elliptical shape for mechanical reasons, as this is advantageous for stability. These considerations have been confirmed. The stresses in the centrifuge casing in the region of the openings are reduced in this way and therefore the durability and stability of the entire centrifuge drum are improved.
In a different form of sugar centrifuges, namely in continuously operating centrifuges, elliptical holes, in other words holes with an elliptical cross-section, are known from EP 1 693 112 B1.
In view of the large number of discontinuously working centrifuges used, specifically in the sugar industry sector, there is considerable interest in a further improvement of the centrifuge casings as well.
The object of the invention is therefore to propose a discontinuous centrifuge, which has a further optimisation of the centrifuge casing.
A further object of the invention is to disclose a method for producing a centrifuge of this type.